1. Field of the Invention
This invention relates to a process for the production of esterquats, in which fatty acid glycerol esters are directly transesterified with tertiary hydroxyamines and then quaternized, and to the use of the products for the production of surface-active formulations.
2. Statement of Related Art
In recent years, quaternized fatty acid triethanolamine ester salts, socalled "esterquats", have acquired increasing significance as ecotoxicologically safe raw materials for fabric softeners cf. O. Ponsati in C.R. CED Congress, Barcelona, 167 (1992) and R. Puchta in C.R. CED Congress, Sitges, 59 (1993)!.
According to the teaching of International patent application WO 91/01295 (Henkel), esterquats are normally produced from triethanolamine or adducts of ethylene oxide with triethanolamine which, in a first step, are partly esterified with linear C.sub.16/18 fatty acids in the presence of hypophosphorous acid and subsequently treated with air. The fatty acid triethanolamine esters are then quaternized, for example with alkyl halides or, preferably, dialkyl sulfates.
Instead of fatty acids themselves, it is desirable for economic reasons directly to use natural fats and oils, from which the fatty acids are obtained, as starting materials for the production of esterquats. However, according to studies conducted by applicants, application of this principle on an industrial scale has hitherto been prevented by the fact that transesterification in the presence of the alkaline catalysts typically used for this type of reaction, namely potassium hydroxide or sodium methylate, generally involves overly long reactor possession times and, in general, leads to discolored products which have to be bleached in an additional, expensive process step.
Accordingly, the problem addressed by the present invention was to provide a process for the production of esterquats based on fats and oils as starting materials which would not have any of the disadvantages mentioned above.